1. Field of the Invention
The present invention relates to a sheet-affixing device that is used for affixing a pressure sensitive adhesive-sheet, such as a protective film, onto a surface of an automobile wheel. Further, the present invention relates to a sheet-supplying device that supplies sheets to the above sheet-affixing device.
2. Description of the Related Art
A wheel for a vehicle, such as an aluminum wheel for an automobile, is shipped after affixing a protective film on its surface, so that the wheel surface is protected from flaw or soil. A pressure sensitive adhesive sheet for a protective film is made from a polypropylene or polyethylene film, of which thickness is about 20 xcexcm to 100 xcexcm. One side of the pressure sensitive adhesive sheet is provided with an adhesive layer of about 10 xcexcm to 30 xcexcm thickness, which comprises acrylic or rubber pressure-sensitive adhesive. The adhesive layer is initially covered with a release sheet and protected. The release sheet is peeled off before applying the protective film to an adherend. Since pressure sensitive adhesive sheets are extremely thin, they can not retain their shape by themselves, so that distortion and wrinkles can easily be produced in affixing operations of a pressure sensitive adhesive sheet. Therefore, there is a great difficulty in carrying out the sheet-affixing operations by an automaton, so that in most cases, skilled workers still manually carry out the above sheet-affixing operations. However, in recent years, there have been some attempts to provide an automaton for affixing pressure sensitive adhesive sheet to a wheel. For example, such a system is disclosed in Japanese Laid-open patent publications (KOKAI) Nos. 7-323953 and 7-40434.
The system disclosed in the above Japanese Laid-Open patent publications Nos. 7-323953 and 7-40434 are large and expensive systems comprising a conveying system, and are exclusively optimized for a certain type of workpiece, so that the devices are only adecuate when affixing pressure sensitive adhesive sheets to mass produced products of the same type. It is difficult to use the above systems for applications that include wheels having various configurations and sizes in the same line, because the above systems require alterations of the line when the shape or size of a wheel manufactured in the line is changed. This leads increases in expense and down time. Therefore, when wheels with different sizes or shapes are required to be dealt with in a line, the sheet-affixing operations still rely upon manual operation by skilled workers.
Therefore, an object of the present invention is to provide a compact sheet-affixing device used in sheet-affixing operations that can easily and efficiently affix a pressure sensitive adhesive sheet to a wheel, and which can be provided at a low cost. Further, the present invention aims to provide a sheet-supplying device that supplies a sheet to the above sheet-affixing device.
According to the present invention, a sheet-affixing device for affixing a pressure sensitive adhesive-sheet onto a wheel is provided. The sheet-affixing device comprises an absorption plate member, an alignment shaft member, and a pressing member.
The absorption plate member is formed in a ring-shape and its exterior diameter is smaller than the diameter of a rim of a wheel. On the bottom surface of the absorption plate member there is a plurality of suction perforations. The alignment shaft member is fitted into the hub of the wheel in order to align the center of the absorption plate member with the center of the wheel. The pressing member is used for pressing a peripheral part of the pressure sensitive adhesive-sheet, suctioned to the bottom surface of the absorption plate member, against the rim. Thereby the peripheral part is affixed to the rim. Further, the pressing member is movable relative to the absorption plate member along the axial direction of the ring-shaped absorption plate member.
Further, according to the present invention, a sheet-supplying device which supplies a pressure sensitive adhesive-sheet to the above-described sheet-affixing device is provided. The sheet-supplying device comprises a table member, a table elevator, a shaft receiving member, and a control unit.
A plurality of ring-shaped pressure sensitive adhesive-sheets is piled up on the table member. The table elevator transfers the table member along the axis of, the ring-shaped pressure sensitive adhesive-sheets. The shaft receiving member receives an alignment shaft member of the sheet-affixing device so as to align the center of the sheet-affixing device to the center of the ring-shaped pressure sensitive adhesive-sheets which are piled up on the table member. The control unit controls the table elevator in order to keep a position of the uppermost sheet of the pressure sensitive adhesive-sheets, piled up on the table member, at a predetermined position where the upper most sheet comes into contact with a bottom surface of the absorption plate member of the sheet-affixing device when the alignment of the sheet-affixing device is achieved.